Bumping this a bit, many offers and sales over 12 keys.

http://www.tf2outpost.com/trade/8676101

Recent Notable Offers :

14 keys

http://www.tf2outpost.com/trade/10943811

Notable Offers:

12 keys

B.M.O.C. + Genuine Shred Alert (12+2)*0.9= 12.6

Bubbling Doctor’s Sack 13*0.9=11.7

N&B Heavy Duty Rag 13*0.9=11.7

12 keys

White Bill + Normal Bill -4 keys 9+7.4-4= 12.4

http://www.tf2outpost.com/trade/11154338

Sold for White bill + 3 keys + brainiac hair + rogue’s col roule + megapixel beard 9+3+(2.495+2+1.33)/5.77*0.9=13.01

http://www.tf2outpost.com/trade/11159627

Notable Offers:

17 keys

Steaming Pencil Pusher (Retracted) 15.5*0.9= 13.95

http://www.tf2outpost.com/trade/12540334

Sold 12 keys.

http://www.tf2outpost.com/trade/12082249

Sold 12 keys.

http://www.tf2outpost.com/trade/12852765

Sold for TW Bill + 4 keys + 6 ref = 13.04

Low end 12 keys because of the two 12 key sales and because it is a commonly offered amount. High end 13 keys not 14 keys because the unusual offer was retracted and because I couldn’t find any sales for the price, while I found two sales for 13 keys. Feedback welcome!